Storage array having multiple controllers

ABSTRACT

A storage system comprises a storage array comprising a plurality of solid state storage devices (SSDs), a first processor comprising a first root complex of the storage system, a plurality of controller devices, and a first switch to interconnect the plurality of SSDs, the first processor and the plurality of controller devices. A first controller device of the plurality of controller devices is to connect the storage system to one or more remote servers. The first controller device is further to receive a first request from a first server of the one or more remote servers and determine whether the first request is a data request or a control request. The first controller device is further to send a first message to a first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the first request is a data request.

RELATED APPLICATIONS

This application is a continuation of pending U.S. patent application Ser. No. 14/597,094 filed Jan. 14, 2015, which is a continuation of U.S. patent application Ser. No. 13/355,823 filed Jan. 23, 2012, now issued as U.S. Pat. No. 8,966,172, and which claims the benefit of U.S. Provisional Application No. 61/560,224 filed on Nov. 15, 2011, all of which are incorporated by reference in their entirety.

FIELD OF TECHNOLOGY

This disclosure relates generally to the field of data storage, and in particular to processor agnostic data storage in a PCIE based shared storage environment.

BACKGROUND

Networked storage arrays may provide an enterprise level solution for secure and reliable data storage. The networked storage array may include a processor (x86 based CPU) that handles the input/outputs (IOs) associated with storage devices in the networked storage array. The number of IOs that the processor can handle may be limited by the compute power of the processor. The advent of faster storage devices (e.g., solid state memory devices) may have increased the number of IOs associated with the storage devices (e.g., from approximately thousands of IOs to millions of IOs). The limited computing power of the processor may become a bottleneck that prevents an exploitation of all the benefits associated with the faster storage devices.

A user may experience significant delays in accessing data from the networked storage arrays due to the processor bottleneck. The delay in access of data may cause the user to get frustrated (e.g., waiting for a long time to access a simple word document). The user may have to waste valuable work time waiting to access the data from the networked storage array. The delay in accessing the data from the networked storage arrays due to the processor bottleneck may even reduce a user's work productivity. The loss of productivity may result in a monetary loss to an enterprise associated with the user as well.

BRIEF DESCRIPTION OF THE FIGURES

Example embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

FIG. 1 illustrates data storage on a shared storage system through the controller device, according to one or more embodiments.

FIG. 2A illustrates an exploded view of the server in FIG. 1, according to one or more embodiments.

FIG. 2B illustrates a server architecture including the controller device, according to one or more embodiments.

FIG. 3 illustrates an exploded view of the disk array of FIG. 1, according to one or more embodiments.

FIG. 4 illustrates an exploded view of the controller device of FIG. 1, according to one or more embodiments.

FIG. 5 illustrates an exploded view of the driver module of FIG. 4, according to one or more embodiments.

FIG. 6 illustrates a data path and a control path in the shared storage system, according to one or more embodiments.

FIG. 7A is a flow diagram that illustrates the control path in the shared storage system including the controller device, according to one or more embodiments.

FIG. 7B is a flow diagram that illustrates the data path in the shared storage system including the controller device, according to one or more embodiments.

FIG. 8 illustrates system architecture of a shared system of FIG. 1 that is scaled using a number of controller devices, according to one or more embodiments.

FIG. 9 is a process flow diagram illustrating a method of processor agnostic data storage in a PCIE based shared storage environment, according to one or more embodiments.

Other features of the present embodiments will be apparent from the accompanying Drawings and from the Detailed Description that follows.

DETAILED DESCRIPTION

In an enterprise environment, numerous servers may require reliable and/or secure data storage. Data from the servers may be stored through a shared storage system. The shared storage may provide a reliable and/or secure data storage through facilitating storage backup, storage redundancy, etc. In one embodiment, in the shared storage system, the servers may be connected to disk arrays through a network. The disk arrays may have a number of storage devices on which the servers may store data associated with the servers. Disk arrays may be storage systems that link a number of storage devices. The disk arrays may be advanced control features, to link the number of storage devices to appear as one single storage device to the server. Storage devices associated with the disk arrays may be connected to the servers through various systems such as direct attached storage (DAS), storage area network appliance (SAN) and/or network attached storage (NAS).

FIG. 1 illustrates data storage on a shared storage system through the controller device, according to one or more embodiments. In particular FIG. 1 illustrates a number of servers 106 a-n, server adapter circuits 110 a-n, network 108, communication links 112 a-n, a disk array 104 and/or a controller device 102.

In one or more embodiments, a number of server's 106 a-n may be connected to a disk array 104 through a network 108 via the communication links 112 a-n. The shared storage system 100 may be described by referring to one server 106 a connected to the disk array 104 through the network 108 via the communication link 112 a merely for ease of description.

In one embodiment, the server 106 a may be a data processing device. In one embodiment, the data processing device may be a hardware device that includes a processor, a memory (not shown in FIG. 1) and a server adapter circuit 110 a-n. In one embodiment, the server 106 may be an x86 based server. In one embodiment, the server 106 a may connect to a network 108 through the server adapter circuit 110 a. The server adapter circuit may be inter alia a network interface card (NIC), a host bus adapter (HBA) and/or a converged network adapter (CNA). In one embodiment, the communication link 112 a may connect the server 106 a to the network 108. In one embodiment, the communication link 112 a may be Ethernet, a Fiber Channel and/or Fiber Channel over Ethernet link based on the server adapter circuit 110 a associated with the server 106 a.

In one embodiment, the data processing device (e.g., server 106 a) may be a physical computer. In one embodiment, the data processing device may be a mobile and/or stationary (desktop computer) device. In another embodiment, the server 106 a may be software disposed on a non-transient computer readable medium. The software may include instructions which when executed through a processor may perform requested services. In one embodiment, the server 106 a may be an application server, a web server, a name server, a print server, a file server, a database server etc. The server 106 a may be further described in FIG. 2A.

In one embodiment the server 106 a may be connected to a disk array to store data associated with the server 106 a. In one embodiment, the network 108 may be a storage area network (SAN) and/or a local area network (LAN). In one embodiment, the server 106 a and/or the disk array 104 may be connected to the network 108 through the communication link 112 a and/or 112 da respectively. In one embodiment, the disk array may be connected to the network through an Ethernet, Fiber Channel (FC) and/or a fiber channel over Ethernet based communication link.

In one embodiment, the disk array 104 may be a storage system that includes a number of storage devices. The disk array 104 may be different from “just a bunch of disks” (JBOD), in that the disk array 104 may have a memory and advanced functionality such as inter alia redundant array of Independent Disks (RAID) and virtualization. The disk array 104 may take a number of storage devices and makes a virtual storage device (not shown in FIG. 1). In one or more embodiments, the virtual storage device may appear as a physical storage device to the server 106 a. In one embodiment, the data from the server 106 a may be stored in a portion of the virtual storage disk. In one embodiment, the disk array 104 may be a block based storage area network (SAN) disk array. In another embodiment, the disk array may be a file based NAS disk array.

In one embodiment, the disk array 104 may include a controller device 102. The controller device 102 may be an interface between the server 106 a and the storage devices associated with the disk array 104. In one embodiment, the storage devices may be solid state drives (SSDs). In one embodiment, a storage device may be a PCIe (Peripheral Component Interconnect-Express) based SSD. In one embodiment, the storage device may be a PCIe disk of a 2.5″ form-factor and operate based on the NVMe protocol. PCIe may be a computer expansion card standard. The PCIe solid state drives may be storage drives designed based on the PCIe standard. SSD form factor specification may define the electrical and/or mechanical standard for a PCIe connection to the existing standard 2.5″ disk drive form factor. An NVMe standard may define a scalable host controller interface designed to utilize PCIe based SSDs.

In one embodiment, the server 106 a may have a storage based request. In one embodiment, the storage based request may be associated with an application running on a server (e.g., host machine). In one embodiment, the storage based request may be associated with a client server operation (e.g., client request where the client is coupled to the server [not shown in Figure]). In one embodiment, the storage based request may include a data request and/or a control request. In one embodiment, the data request may be associated with a data that the server 106 a may need to store in the disk array 104. The data request may include a request to write a data to a storage device of the disk array 104 and/or read a data from a storage device of the disk array 104. In one embodiment, the control request from the server 106 a may be associated with checking a status of the storage disks associated with the disk array 104. In one embodiment, an example of a control request may be when a server 106 a requests the health of the storage devices, a total storage space available, etc.

In the embodiment of FIG. 1, the server 106 a may forward a storage based request to the disk array through the network 108 via a communication link 112 a. In one or more embodiments, the controller device 102 may receive the storage request from the server 106 a. In one or more embodiments, the controller device 102 may process the storage based request. In one embodiment, the controller device 102 may distinguish the storage based request through decoding the storage based request. The controller device 102 may distinguish the storage based request as a control request and/or a data request. In one embodiment, the controller device 102 may convert the data request to a format compatible with the storage device of the disk array 104. In one embodiment, the controller device 102 may determine where the storage based request may be forwarded to, based on whether the storage request is distinguished to be a control request and/or a data request. In one embodiment, based on a completion of the storage based request, the controller device 102 of the disk array 104 may inform the respective completion of the server 106 a. The disk array 104 may be further described in FIG. 3.

Now refer to FIG. 3 and FIG. 1. FIG. 3 illustrates an exploded view of the disk array of FIG. 1, according to one or more embodiments. In particular, FIG. 3 illustrates a controller device 102, a switch 306, a processor (CPU) of the disk array 302, a memory 304, a communication link 112 and/or a number of storage devices 308 a-n.

In one embodiment, data from the server 106 may be stored in the number of storage devices 308 a-n of the disk array 104. In one embodiment, the storage devices 308 a-n may be linked together to appear as one virtual storage device through the processor of the disk array 302. In one embodiment, the total storage space of the virtual storage device may be equal to a combination of the storage space of the number of storage devices 308 a-n that are linked together. In one embodiment, total storage space associated with the number of storage devices 308 a-n may be partitioned between the servers 106 a-n through the processor of the disk array 302. Each server of the number of servers 106 a-n may be assigned an addressable space in the number of storage devices 308 a-n through the processor of the disk array 302. In one embodiment, storage space assigned to each server of the number of servers 106 a-n may be spread among different storage devices 308 of the number of storage devices 308 a-n. In one embodiment, the servers 106 a-n may access (e.g., address) the number of storage devices 308 a-n through virtual addresses assigned by the processor of the disk array 302. In one embodiment, the processor 302 may translate the virtual address to a physical address. In one embodiment, all the address translations (virtual to physical) may be recorded in a translation table. In one embodiment, the processor 302 may send the translation table to the controller device 102. In one embodiment, the translation table may reside in the controller device. In one embodiment, the processor may transfer the address translation. In one embodiment, the processor 302 may be root complex.

In one embodiment, when the disk array 104 powers up, the processor 302 may send a discovery request to identify the different devices associated with the disk array 104. In one embodiment, every device associated with the disk array 104 may respond to the discovery request of the processor 302. Based on the response, the processor 302 may have information regarding the number of storage devices 308 a-n such as the total storage space associated with the number of storage devices 308 a-n, health of each storage device, etc. In one embodiment the processor of the disk array 302 may divide the total addressable memory to allocate space to different devices that request addressable space. In one embodiment, all the devices of the disk array may be memory mapped. The division and/or mapping of the addressable space may reside in the memory 304 and/or the processor 302. In one embodiment, the memory 304 may be a transient and/or non-transient memory.

In one embodiment, the processor 302 may associate the controller device 102 with at least one of the number of storage devices 308 a-n. In one embodiment, the processor may associate the server 106 with at least one of the number of storage devices 308 a-n through associating the controller device 102 to at least one of the number of storage devices 308 a-n. In one embodiment, the processor 302 may record the association of the controller device 102 and/or the server 106 with at least one of the number of storage devices 308 a-n in a mapping table. In one embodiment, the mapping table (not shown in FIG. 3) may be forwarded to the controller device 102. In one embodiment, the mapping table may reside in the controller device 102. In an example embodiment, the server 106 a may be allocated addressable space in storage device 1 308 a and addressable space in storage device 2 308 b. In the example embodiment, the mapping table residing in the controller device 102 (generated through the processor 302 and forwarded to the controller device 102) may have an entry that shows the mapping of the server 106 a to the storage device 1 308 a and storage device 2 308 b.

In one embodiment, the controller device 102 may be connected to the number of storage devices 308 a-n through a switch 306. In one embodiment the switch 306 may be part of the CPU 302. In one embodiment, the switch 306 may be an interface between the controller device 102, the number of storage devices 308 a-n, and/or processor of the disk array 302. In one embodiment, the switch 306 may transfer communication between the controller device 102, the number of storage devices 308 a-n, and/or processor of the disk array 302. In one embodiment, the switch 306 may be a PCIe switch. In one embodiment, the PCIe switch 306 may direct communications between the controller device 102 and the number of PCIe storage devices (e.g., number of storage devices 308 a-n). In another embodiment of FIG. 3, the disk array may include a number of controller devices (102 a-n) as well. The number of controller devices 102 a-n may be connected to the number of storage devices 308 a-n through the switch 306, which is described later in the embodiment of FIG. 8. In one embodiment, the storage devices 308 a-n may be PCIe solid state drives. In one embodiment, the data from the server 106 may be stored in the storage devices 308 a-n (e.g., NVMe based PCIe SSDs).

In one embodiment, storage based requests may be sent from the server 106 to the disk array. In one embodiment, the storage based request may be a data write request, data read request and/or control request. In one embodiment, the controller device 102 of the disk array may receive the storage based request. In one embodiment, the controller device 102 may process the storage based request. The controller device 102 may process the storage based request through an NVMe based paired queue mechanism.

In one embodiment, a paired queue may include a submission queue and a completion queue (not shown in FIG. 3). In one embodiment, the submission queue may be a circular buffer with a slot size of n-bytes. In one embodiment, slot size may be determined by the size of the command that may be written in the submission queue. In one embodiment, the size of the command may be determined by the NVMe standard. In one embodiment, the submission queue may be used by the controller device 102 to submit commands for execution by the storage device 308. In one embodiment, the storage device 308 may retrieve the commands and/or requests from the submission queue to execute them. In one embodiment, the commands and/or requests may be fetched from the submission queue in order. In one embodiment, the storage device 308 may fetch the commands and/or requests from the submission queue in any order as desired by the storage device 308. In one embodiment, the commands and/or requests may be processed by the storage device 308 in any order desired by the storage device 308. In one embodiment the completion queue may be a circular buffer with a slot size of n-bytes used to post status for completed commands and/or requests. In one embodiment, once the storage device completes a command and/or request, the completion status is written in the completion queue and the storage device 308 issues an interrupt to the controller device 102 to read the completion status and forward it to the server 106. In one embodiment, the paired queue mechanism may allow a number of controller devices 102 a-n to access a single storage device 308 (e.g., 308 a). In one embodiment, the single storage device 308 may be substantially simultaneously accessed by the number of controller devices 102 a-n based on how the entry in the submission queue is processed. In one embodiment simultaneous access may refer to the ability to write into the queue substantially simultaneously (disregarding the delay in writing to the queue and the delay to write to the queue in order which may be negligible). In one embodiment, each controller device 102 (e.g., 102 a) of the number of controller devices 102 a-n (not shown in Figure) may be associated with a number of storage devices 308 a-n based on the paired queue mechanism.

In one embodiment, each storage device of the number of storage devices 308 a-n may be associated with a submission queue and a completion queue. In one embodiment, the submission queue and the completion queue may be mapped to reside locally in the controller device 102. In one embodiment, the processor 302 may map the paired queues associated with the storage device to the controller device 102. In one embodiment, a mapping of the paired queue associated with a storage device to the controller device may be recorded in an interrupt table. In one embodiment, the processor 302 may generate the interrupt table. In one embodiment, the processor 302 may forward the interrupt table to the associated storage device. In one embodiment, the interrupt table may reside in the storage device.

In one embodiment, the paired queues reside locally in a memory of the controller device 102. The controller device may be memory mapped. Similarly, the translation table and the mapping table residing in the controller device 102 may all be stored in a memory of the controller device 102. In one embodiment, the processor 302 may generate and/or set up the paired queues. The controller device 102 may be described in FIG. 4.

FIG. 4 illustrates an exploded view of the controller device of FIG. 1, according to one or more embodiments. In particular FIG. 4 illustrates an adapter circuit 404, a logic circuit 402, a driver module 406 and/or a storage interface circuit 408.

In one or more embodiments, the controller device 102 may include an adapter circuit 404, a logic circuit 402, a driver module 406 and/or a storage interface circuit 408. In one embodiment, a storage based request from the server 106 may be received by the controller device 102. In one embodiment, the storage based request may be received through the adapter circuit 404 of the controller device 102. In one embodiment, the adapter circuit 404 of the controller device 102 may be the interface of the controller device 102 to connect to the network 108. In one embodiment, the adapter circuit 404 may be a HBA, NIC and/or a CNA. In one embodiment, the interface may be FC MAC (Media Access Control), Ethernet MAC and/or FCoE MAC to address the different network interfaces (e.g., FC, Ethernet and/or FCoE). In one embodiment, the adapter circuit 404 may manage protocol specific issues. In one embodiment, the adapter circuit 404 may forward the storage based request to the logic circuit 402. In one embodiment, the controller device 102 may be included in the disk array 104. In one embodiment, the controller device 102 may be included in the server 106 (e.g., host machine).

In one embodiment, the logic circuit 402 may receive the storage based request forwarded from the adapter circuit 404. In one embodiment, the logic circuit 402 may process the storage based request to distinguish a nature of the storage based request. In one embodiment, the storage based request may be a data request and/or a control request. In one embodiment, the logic circuit 402 may distinguish the nature of the storage based request through decoding the storage based request. In one embodiment, the logic circuit 402 may terminate the network protocol. In one embodiment, the logic circuit 402 may provide protocol translation from the network protocol to the storage device based protocol. In one embodiment, the logic circuit 402 may translate the network protocol to an NVM Express protocol. In one embodiment, the logic circuit 402 may convert a format (e.g., network protocol FC, iSCSI, etc.) of the data request to another format compatible with the storage device 308 (e.g., NVME). In one embodiment, the protocol conversion of the control request may be implemented by a driver module running on the processor 302. In one embodiment, the driver module 406 of the controller device may be a data request based driver module. The driver module 406 may be a NVME driver module. The control request based driver may run on the processor 302. In one embodiment, the NVME driver may be separated between the controller device 102 and the processor 302.

In one embodiment, the logic circuit 402 may direct the data request compatible with the storage device 308 to the storage device 308 of the disk array 104 coupled to the controller device 102 agnostic to a processor 302 of the disk array 104 based on the mapping table residing in the memory (e.g., memory mapped) of the controller device 102. In one embodiment, when the logic circuit 402 distinguishes the storage based request to be a data request, the logic circuit 402 converts the data request to an NVME command corresponding to the data request. In one embodiment, the NVME command may be written in the submission queue of a paired queue residing in the controller device 102. In one embodiment, if the logic circuit 402 distinguishes the storage based request to be a control request, then the logic circuit 402 forwards the control request to the processor 302. The processor 302 then handles the control request. In one embodiment, the data request may be processed agnostic to the processor 302. In one embodiment, the controller device 102 directly processes the data requests without involving the processor 302. Handling of the data request and control request may be further described in FIG. 6 and FIG. 7A-FIG. 7B. In one embodiment, the logic circuit 402 may route the data request directly to the appropriate storage device 308 by-passing the processor 302. In one embodiment, the logic circuit 402 of the controller device 102 may route the data requests directly to the appropriate storage device 308 based on the mapping table that resides in the controller device 102. In one embodiment, the mapping device illustrates a mapping of each storage device to respective controller device.

In one embodiment, the storage interface circuit 408 may provide an interface to the switch 306. The switch 306 may be a PCIe switch. In one embodiment, the storage interface circuit 408 may be a multi-function PCIe end-point. In one embodiment, the PCIe end-point (e.g., storage interface circuit 408) may act as a master. In one embodiment, the controller device may communicate to the storage device through a peer to peer mechanism. In one embodiment, the storage device 308 may be the target. In one embodiment, the storage device 308 may be the master. In one embodiment, the storage interface circuit 408 may issue commands associated with the data request. The commands may be written into the submission queue for further processing.

In one embodiment, the driver module 406 may be a hardware circuit. In one embodiment, the driver module 406 may be a software module. In one embodiment, the driver module 406 (software module) may be a set of instructions that when executed may cause the adapter circuit 404, the logic circuit 402 and/or the storage interface circuit 408 to perform their respective operations. The driver module 406 may be further described in FIG. 5.

Now refer to FIG. 5, FIG. 4 and FIG. 1. FIG. 5 illustrates an exploded view of the driver module of FIG. 4, according to one or more embodiments. In particular FIG. 5 illustrates a mapping module 502, an interrupt module 504, a protocol conversion module 506, a translation module 508, the adapter module 510, the logic module 512 and/or the storage interface module 514.

In one embodiment, the driver module may be a set of instructions which when executed may cause the various circuits of the controller device 102 to perform their respective operations as described in FIG. 4. In one embodiment, the adapter module 510 may enable the adapter circuit 404 to manage protocol specific issues. In one embodiment, the adapter module 510 of the driver module 406 may cause the adapter circuit 404 to receive the storage request from the server 106 via the network 108. The adapter module 510 may enable the adapter circuit to forward the storage based request to the logic circuit 402 of the controller device 102.

In one embodiment, the logic module 512 may be a set of instructions, which when executed may cause the logic circuit 402 of the controller device 102 to convert the network protocol to a NVME protocol. In one embodiment, the logic module 512 may communicate with the protocol conversion module 506 to convert the format of the data request (e.g., network protocol) to another format compatible with the storage device 308 (e.g., NVME protocol). In one embodiment, the protocol conversion module 506 may identify a protocol associated with the data request. In one embodiment, the protocol associated with the data request may be FC and/or iSCSI. In one embodiment, the protocol conversion module 506 may convert the network protocol to an NVME protocol through generating NVME commands corresponding to the data request. In one embodiment, the logic module may initiate a data flow through submitting (e.g., write) the NVME commands corresponding to the data request to a submission queue of a paired queue that resides in the memory of the controller device 102.

In one embodiment, the logic module 512 may communicate with the mapping module 502 to route the data request to the respective storage device 308 based on the mapping table. In one embodiment, the mapping module 502 may refer to a mapping table that includes an association of the controller device 102 and/or the server 106 to the storage device 308. In one embodiment, the logic module 512 may also route the storage based request from the controller device 102 to the processor 302 of the controller device 102. In one embodiment, the mapping table, may be a mapping of a logical volume presented to each host machine (e.g., server 106) to the logical volume of each individual storage device 308. In one embodiment, a typical disk may present itself to the host as one contiguous logical volume. In one embodiment, the storage device 308 may take this logical space (e.g., logical volume) presented by each disk and create a pool of multiple logical volumes which in turn is presented to the individual hosts. The mapping table may be a mapping from the logical volume presented to each host to the logical volume of each individual disks. The mapping table may be separate from a logical to physical mapping table or a physical to logical mapping table. In one embodiment, the mapping table may be functionally different from a logical to physical mapping table or a physical to logical mapping table. In one embodiment, the mapping table may be dynamically updated based on a status of the storage disk.

In one embodiment, the logic module 512 may communicate with the interrupt module 504 to process an entry of the completion queue made by the storage device 308. In one embodiment, a completion status may be forwarded to the corresponding server. In one embodiment, the interrupt module 504 may communicate with the logic module 512 to respond to an interrupt received from the storage device 308.

In one embodiment, the server 106 may communicate a storage based request with the storage device 308 of the disk array 104 through a virtual address of the storage device 308. In one embodiment, the logic module 512 may communicate with the translation module 508 to convert the virtual address associated with the storage device 308 to a physical address of the storage device 308. In one embodiment, the translation module 508 may refer to a translation table that includes an association of the virtual address of storage devices 308 with the physical address of the storage devices 308.

In one embodiment, the storage interface module 514 may issue commands to the storage interface circuit 408 to route the NVME commands to the appropriate storage device 308. In one embodiment, the storage interface circuit 408 may inform the storage device 308 of an entry in the submission queue. In one embodiment, the storage interface circuit 408 may communicate with the switch 306 to forward the NVME commands to the responsible storage device 308. The communication path of the data request and the control request may be referred to as data path and control path respectively hereafter. The routing of the data request and the control request are further described in the embodiment of FIG. 6.

Now refer to FIG. 6, FIG. 1, FIG. 3 and FIG. 4. FIG. 6 illustrates a data path and a control path in the shared storage system, according to one or more embodiments. In particular, FIG. 6 illustrates a number of servers 106 a-n, server adapter circuits 110 a-n, a network 108, communication links 112 a-n, a disk array 104, a controller device 102, a data path 602, a control path 604, a switch 306, a number of storage devices 308 a-n, a processor 302 and/or a memory 304.

In an example embodiment of FIG. 6, a server 106 a (e.g., host system) may generate a storage based request and/or receive a storage based request from a client device (not shown in FIG. 6). In one embodiment, the server 106 a may forward the storage based request to the disk array 104 through the network 108. In one embodiment, the storage based request may be communicated to the disk array through a communication link 112 a. In one embodiment, the communication link 112 a may employ a fiber channel protocol and/or iSCSI protocol to communicate the storage based request to the disk array 104 via the network 108. In one embodiment, the controller device 102 of the disk array 104 may receive the storage based request from the server 106 a via the network 108.

In the example embodiment, if the storage based request is a SCSI command the storage based requests may be placed (e.g., written) in a SCSI queue (not shown in FIG. 6). In one embodiment, the queue may be managed through a buffer management module (not shown in FIG. 6). In one embodiment, the SCSI commands residing in the SCSI queue may be decoded before the storage based request is converted to a NVME protocol from the SCSI protocol. In one embodiment, the SCSI commands from the server 106 may be compressed before they are transmitted to the disk array 104 via the network 108. In one embodiment, they may be compressed to efficiently utilize the network bandwidth. In one embodiment, the SCSI commands may be decompressed at the controller device 102.

In one embodiment, the controller device 102 may distinguish the storage based request as a data request and/or a control request. In one embodiment, the data request may be a data write request and/or data read request. In one embodiment, the data write request and/or data read request may include a parameter that indicates the address of the storage device 308 to which the data is to be written and/or the address of the storage device 308 from which a data must be read. In one embodiment, the address associated with the storage device 308 included in the data request may be a virtual address of the storage device. In one embodiment, the controller device 102 may translate the virtual address associated with the storage device to a physical address of the storage device through a translation module 508. In one embodiment, the controller device may refer to a translation table to translate the virtual address to a physical address. In one embodiment, an entry of the translation table may indicate a virtual address and the corresponding physical address of the virtual address on the storage device 308. In one embodiment, the translation table may be merged with a mapping table. In one embodiment, an entry of the mapping table may include an association of the controller device 102 and/or server 106 a with a corresponding storage device of the number of storage devices 308 a-n. In one embodiment, the controller device 102 may determine the storage device associated with the controller device 102 and/or the server 106 a through the mapping table. In one embodiment, once the storage device 308 associated with the server 106 a and/or the controller device 102 has been determined, the controller device 102 may convert the SCSI commands to a corresponding NVME command through a protocol conversion module 506 of the controller device 102. In one embodiment, a logic module 512 and/or the storage interface module 514 of the controller device 102 may initiate a data flow through submitting the NVME command corresponding to the data request in a submission queue of a paired queue associated with the respective storage device 308. In one embodiment, the storage interface module 514 may alert the storage device 308 of an entry in the submission queue associated with the storage device 308. In one embodiment, the storage device may access the submission queue residing in the controller device and process the corresponding command.

In one embodiment, the storage device 308 may communicate with the controller device 102 through the switch 306. In one embodiment, the data request may be routed to the respective storage device 308 (e.g., 308 a). In one embodiment, routing the data request from the controller device 102 to the storage device 308 may be agnostic to the processor 302. In one embodiment, the controller device 102 may route the data request directly from the controller device 102 to the appropriate storage device by by-passing the processor 302. In one embodiment, the data path 602 may be a path taken by the data request. In one embodiment, the data path may start from a server 106 (e.g., 106 a) and may reach the controller device 102 through the network 108. The data path 602 may further extend from the controller device 102 directly to the storage device 308 through the switch 306.

In one embodiment, the control path 604 may be a path taken by the control request. In one embodiment, the control path 604 may start from the server 106 (e.g., 106 a) and reach the controller device 102 through the network 108. The control path 604 may further extend from the controller device 102 to the processor 302. In one embodiment, the controller device 102 may route all the control requests to the processor 302. In one embodiment, the processor 302 may communicate with the number of storage devices 308 a-n to gather information required according to the control request. In another embodiment, each storage device 308 of the number of storage devices 308 a-n may send a status of the storage device of the number of storage devices 308 a-n to the processor 302. The processor 302 may have a record of the status of the storage devices 308 a-n.

In one embodiment, once the data request is processed by the storage device 308, the storage device 308 may issue an interrupt to the controller device 102. In one embodiment, the storage device 308 may issue and interrupt to the controller device 102 based on an interrupt table. In one embodiment, the interrupt module 514 of the controller device may handle the interrupt from the storage device 308. In one embodiment, the controller device may read the completion queue when it receives an interrupt form the storage device 308. The process of handling a control request and/or a data request may be further described in FIG. 7A and FIG. 7B.

Now refer to FIG. 7A, FIG. 7B and FIG. 6. FIG. 7A is a flow diagram that illustrates the control path in the shared storage system including the controller device, according to one or more embodiments. In particular, FIG. 7A illustrates a server 106 (host device), a controller device 102, a processor 302 and/or a storage device 308.

In one embodiment, in operation 702 the server 106 may transmit a storage based request to the controller device 102. In one embodiment, in operation 704, the controller device may receive the storage based request through the adapter circuit 404. In one embodiment, the controller device 102 may decode the storage based request to distinguish the storage based request and/or a nature of the storage based request as a control request and/or a data request. In one embodiment, if the storage based request is a control request, the controller device 102 may route the control request to the processor 302 in operation 706. In one embodiment, in operation 708, the processor 302 may receive the control request. In one embodiment, the controller device 102 may route the control request to the controller device. In one embodiment, the controller device 102 may route the control request to the processor 302 through writing the control request to a control queue residing locally in the controller device 102 or the processor memory 304 (e.g., Operation 705). In one embodiment, the controller device 102 may alert the processor 302 of an entry in the control submission queue. In one embodiment, the processor 302 may fetch the control request from the queue (e.g., Operation 706).

In one embodiment, the processor 302 may have a status of all the storage devices 308 a-n of the disk array. In one embodiment, the processor 302 may forward a status of the storage device 308 (e.g., 308 a) to the controller device 102 based on the control request, in operation 710. In one embodiment, the processor may forward the status of the storage device 308 through writing a completion status in the completion control queue (e.g., Operation 709). In one embodiment, the processor 302 may issue an interrupt before and/or after the completion status is written in the completion queue. In one embodiment, the controller device 102 may forward a response to the control request to the server 106, in operation 712.

In one embodiment, if the processor 302 does not have the status of the requested storage device 308, the processor 302 may request a status from the storage device 308 in operation 714. In one embodiment, in operation 716, the storage device 308 may respond to the processor 302 with a status of the storage device 308. In one embodiment, the status of the storage device and/or completion of the control request may be transmitted to the server 106 that issued the control request through operation 718, 719 and/or 720.

FIG. 7B is a flow diagram that illustrates the data path in the shared storage system including the controller device, according to one or more embodiments. In particular, FIG. 7B illustrates a server 106 (host device), a controller device 102, a processor 302 and/or a storage device 308.

In one embodiment, in operation 702 the server 106 may transmit a storage based request to the controller device 102. In one embodiment, in operation 704, the controller device may receive the storage based request through the adapter circuit 404. In one embodiment, the controller device 102 may decode the storage based request to distinguish the storage based request as a control request and/or a data request. In one embodiment, if the storage based request is a data request, the controller device 102 may route the data request directly to the respective storage device 308, bypassing the processor 302. In one embodiment, the controller device 102 may route the data request to the storage device 308 through writing the data request (e.g., corresponding NVME command) in the submission queue associated with the storage device 308, in operation 730. In one embodiment, the controller device may alert the storage device of an entry in the submission queue associated with the storage device 308 in operation 732. In one embodiment, the controller device 102 may alert the storage device 308 through changing an associated bit (e.g., may be 1 bit that indicates an event) in the storage device that may indicate an entry in the submission queue associated with the storage device 308.

In one embodiment, the storage device 308 may fetch the data request from the submission queue and process the data request in operation 734. Also in operation 734, when the data request is processed the storage device 308 may write a completion status in the completion queue associated with the storage device 308. In one embodiment, a completion status may indicate that the data request in the submission queue has been processed. In one embodiment, the storage device 308 may send an interrupt signal to the controller device 102 once the completion status has been written into the completion queue. In one embodiment, the completion status may be entered in the completion queue after an interrupt is issued. In one embodiment, in operation 735 an entry may be made to the completion queue. In one embodiment, in operation 736, the controller device 102 may read the completion status from the completion queue and then in operation 738, the controller device 102 may forward the completion status to the server 106 that issued the data request.

In another embodiment of FIG. 1, the shared storage system 100 may have a number of controller devices 102 a-n, as illustrated in FIG. 8. Now refer to FIG. 1 and FIG. 8. FIG. 8 illustrates a system architecture of a shared system of FIG. 1 that is scaled using a number of controller devices, according to one or more embodiments. In particular, FIG. 8 illustrates a number of controller devices 102 a-n, a number of processors 302 a-b, a number of switches 306 a-b and/or a number of storage devices 308 a-n.

In an example embodiment, the paired queue (submission and completion) of the storage device 308 a that represents a submitted storage request and a completed storage request respectively may be associated with the controller device 102 a. In one embodiment, the architecture of the disk array 104 may be made scalable through associating the pair of the submission queue and the completion queue of the storage device 308 with a controller device 102. In one embodiment, a storage device 308 a may be mapped to a number of controller devices 102 a-n through associating the paired queue of the storage device 308 a to each of the number of controller devices 102 a-n. In another embodiment, a controller device 102 a may be mapped to a number of storage devices 308 a-n. In one embodiment, scaling the shared storage system through mapping one controller device 102 to a number of storage devices and mapping one storage device to a number of controller devices may be enable sharing a storage device (PCIE disk) with a number of controller devices 102 a-n. In one embodiment, data associated with the data requests may be striped across a number of storage disks 308 a-n. In one embodiment, striping data across a number of storage devices 308 a-n may provide a parallelism effect.

In one embodiment, bypassing the processor 302 in the data path 602 may enable a scaling of the shared storage system as shown in FIG. 8. In one embodiment, the shared storage system may be made scalable when a single controller device may access (through being mapped) a number of PCIe drives (e.g., storage devices 308 a-n). In one embodiment, the number of controller devices 102 a-n may be coupled to a number of storage devices 308 a-n through a number of switches 306 a-b. In one embodiment, the disk array 104 may have multiple processors 302 a-b. In one embodiment, the controller device 102 may be included with the server 106 to provide a virtual NVMe service at the server 106. The virtual NVME may be further disclosed in FIG. 2A and FIG. 2B.

Now refer to FIG. 2A and FIG. 2B. FIG. 2A illustrates an exploded view of the server in FIG. 1, according to one or more embodiments. In particular, FIG. 2A illustrates a server 106, a server processor 202, a server memory 204, a root complex 206, a switch 208, a number of PCIE end points 210 a-c, a network 108, a number of communication links 112 nic, 112 hba and 112 cna, a controller device 102 and/or a disk array 104.

In one embodiment, the server processor 202 may initiate a discovery when the server processor 202 powers up. In one embodiment, the server processor 202 may send a discovery request (e.g., configuration packet) to the switch 208 (e.g., PCIE switch). In one embodiment, the switch 208 may broadcast the discovery request to the number of PCIE end points 210 a-c. In one embodiment, the switch may route requests through an identifier based routing (e.g., bus, device and function (BDF) identifier) and/or an address based routing.

In one embodiment, the root complex 206 may assign a device address to each of the PCIE end points 210 a-n. In one embodiment, the root complex 206 may be the master. In one embodiment, an application (associated with the server 106) may write a storage based request to the server memory 204. In one embodiment, the PCIE end point (e.g., 112 a, 112 b or 112 c) may fetch the data from the server memory 204. In one embodiment, the PCIE end point 112 (112 a, 112 b or 112 c) may transmit the storage based request from the server to the disk array 104 through the network 108. In one embodiment, the PCIE end point 112 may interface with the switch 208.

In one embodiment, the controller device 102 receives the storage based request from the server and may process the storage based request. In one embodiment, if the storage based request is a data request, the storage based request may be forwarded to a storage device through the controller, by-passing the processor 302 of the disk array 104. In one embodiment, the controller device 102 may be installed on the server 106.

Now refer to FIG. 2B. FIG. 2B illustrates a server architecture including the controller device, according to one or more embodiments. In particular, FIG. 2B illustrates a server 106, a server processor 202, a server memory 204, a root complex 206, a switch 208, a number of PCIE end points 210 a-c, a network 108, a number of communication links 112 nic, 112 hba and 112 cna, a controller device 102, a disk array 104 and/or a controller device 102 s.

In one embodiment, the server processor 202 may initiate a discovery when the server processor 202 powers up. In one embodiment, the server processor 202 may send a discovery request (e.g., configuration packet) to the switch 208 (e.g., PCIE switch). In one embodiment, the switch 208 may broadcast the discovery request to the number of PCIE end points 210 a-c. In one embodiment, the switch may route requests through an identifier based routing (e.g., bus, device and function (BDF) identifier) and/or an address based routing.

In one embodiment, the root complex 206 may assign a device address to each of the PCIE end points 210 a-n. In one embodiment, the root complex 206 may be the master. In one embodiment, the controller device 102 s in the server 106 may portray characteristics of a PCIE end point. In one embodiment, the controller device 102 s in the server 106 may appear to the server processor 202 and/or root complex 206 as a PCIE solid state storage device directly plugged to the server 106.

In one embodiment, an application (associated with the server 106) may write a storage based request to the server memory 204. In one embodiment, the server processor 202 and/or the root complex 206 may trigger a bit in the controller device 102 s to alert the controller device 102 s of an entry in the server memory 204. The controller device 102 s may fetch the storage based request and forward it to the controller device 102 in the disk array 104. In one embodiment, the controller device of the server 102 s may communicate the storage based request to the disk array 104 through a communication link 112. The communication link 112 may be FC, Ethernet and/or FCoE. In one embodiment, the controller device 102 s may have a unique interface of its own to communicate with the network which is different from FC, Ethernet and/or FCoE. The controller device 102 s may be provide virtual NVME experience at the host machine (e.g., server 106).

In one embodiment, an NVMe based PCIe disk may include a front end NVMe controller and backend NAND flash storage. A virtual NVMe controller card (controller device 102 s) may include an NVMe front end and the back end storage part may be replaced by an Ethernet MAC, in an example embodiment of FIG. 2B. The host machine (e.g., server 106) may think it's interfacing with a standard NVMe PCIe disk. However, instead of the storage being local it will be remotely accessed over the Ethernet network, in the example embodiment. The host driver may then generate the NVMe commands. In the example embodiment, the logic behind the virtual NVMe controller may encapsulate these NVMe commands into Ethernet packets and route them to the appropriate controller device 102 of the disk array 106, where it may be de-encapsulated and forwarded to the real PCIe disk with the appropriate address translation. In an example embodiment of FIG. 8, the controller device 102 of the disk array 106 may get simplified as all it needs to do is address translation as the protocol remains the same (e.g., since the protocol translation to NVME may have been performed at the controller device 102 s on server side (host machine).

FIG. 9 is a process flow diagram illustrating a method of processor agnostic data storage in a PCIE based shared storage environment, according to one or more embodiments. In one embodiment, in operation 902, a storage based request received at an adapter circuit of a controller device associated with a disk array from a host machine that is at a remote location from the disk array through a network via the controller device may be processed to direct the storage based request to at least one of a processor of the disk array and a plurality of storage devices of the disk array. In one embodiment, in operation 904, a nature of the storage based request may be distinguished to be at least one of a data request and a control request via a logic circuit of the controller device through decoding the storage based request based on a meta-data of the storage based request. In one embodiment, in operation 906, a format of the data request may be converted to another format compatible with the plurality of storage devices through the logic circuit of the controller device. In one embodiment, in operation 908, the data request in the other format compatible with the storage device may be routed through an interface circuit of the controller device, to at least one storage device of the plurality of storage devices of the disk array coupled to the controller device agnostic to a processor of the disk array to store a data associated with the data request based on a mapping table, residing in a memory of the controller device that is mapped in a memory of the disk array, that represents an association of the at least one storage device of the plurality of storage devices to the controller device.

Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. For example, the various devices and modules described herein may be enabled and operated using hardware, firmware and software (e.g., embodied in a machine readable medium). For example, the various electrical structure and methods may be embodied using transistors, logic gates, and electrical circuits (e.g., application specific integrated (ASIC) circuitry and/or in digital signal processor (DSP) circuitry).

In addition, it will be appreciated that the various operations, processes, and methods disclosed herein may be embodied in a machine-readable medium and/or a machine accessible medium compatible with a data processing system (e.g., a computer devices), may be performed in any order (e.g., including using means for achieving the various operations). Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. 

What is claimed is:
 1. A storage system comprising: a storage array comprising a plurality of solid state storage devices (SSDs); a first processor comprising a first root complex of the storage system; a plurality of controller devices; and a first switch to interconnect the plurality of SSDs, the first processor and the plurality of controller devices; wherein a first controller device of the plurality of controller devices is to: connect the storage system to one or more remote servers; receive a first request from a first server of the one or more remote servers; determine whether the first request is a data request or a control request; and send a first message to a first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the first request is a data request.
 2. The storage system of claim 1, further comprising: a second processor comprising a second root complex for the storage system; and a second switch to interconnect the plurality of SSDs, the second processor and the plurality of controller devices.
 3. The storage system of claim 1, wherein the first processor is to: determine a plurality of endpoints of the storage system, the plurality of endpoints comprising the plurality of controller devices and the plurality of storage devices; allocate memory addresses to each of the plurality of endpoints; generate a mapping table comprising one or more of the memory addresses allocated to one or more of the plurality of endpoints; and send the mapping table to at least the first controller device via the first switch.
 4. The storage system of claim 3, wherein the first message is sent to the at least one SSD based on the mapping table.
 5. The storage system of claim 1, further comprising: a second controller device of the plurality of controller devices to: connect the storage system to one or more additional remote servers; receive a second request from a second server of the one or more additional remote servers; determine whether the second request is a data request or a control request; and send a second message to the first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the second request is a data request.
 6. The storage system of claim 1, wherein the first processor is to: determine a first paired queue associated with the first SSD, the first paired queue comprising a first submission queue and a first completion queue, wherein the first paired queue is to reside in a memory of the first controller device; and determine a second paired queue associated with a second SSD of the plurality of SSDs, the second paired queue comprising a second submission queue and a second completion queue, wherein the second paired queue is to reside in the memory of the first controller device.
 7. The storage system of claim 1, wherein the first controller device is further to: receive a second request from a second server of the one or more remote servers; determine whether the second request is a data request or a control request; and forward the second request to the first processor via the first switch responsive to a determination that the second request is a control request.
 8. The storage system of claim 1, wherein the plurality of controller devices comprises a first number of controller devices, the plurality of SSDs comprises a second number of SSDs, and the first number of controller devices is different from the second number of SSDs.
 9. The storage system of claim 1, wherein the first root complex is a master and the plurality of SSDs and the plurality of controller devices are peers.
 10. The storage system of claim 1, wherein the first controller device is to: expose a first virtual drive to the first server, wherein the first request comprises a virtual address of the first virtual drive; and translate the virtual address into a physical address of at least one SSD of the plurality of SSDs using a translation table.
 11. A method comprising: connecting, by a first controller device of a storage system, the storage system to one or more remote servers, wherein the storage system comprises 1) a plurality of controller devices comprising the first controller device, 2) a first processor comprising a first root complex of the storage system, 3) a storage array comprising a plurality of solid state storage devices (SSDs), and 4) a first switch to interconnect the plurality of SSDs, the first processor and the plurality of controller devices; receiving, by the first controller device, a first request from a first server of the one or more remote servers; determining, by the first controller device, whether the first request is a data request or a control request; and sending, by the first controller device, a first message to a first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the first request is a data request.
 12. The method of claim 11, further comprising: determining, by the first processor, a plurality of endpoints of the storage system, the plurality of endpoints comprising the plurality of controller devices and the plurality of SSDs; allocating, by the first processor, memory addresses to each of the plurality of endpoints; generating, by the first processor, a mapping table comprising one or more of the memory addresses allocated to one or more of the plurality of endpoints; and sending, by the first processor, the mapping table to at least the first controller device via the first switch.
 13. The method of claim 12, wherein the storage system further comprises a second processor comprising a second root complex and a second switch to interconnect the plurality of SSDs, the second processor and the plurality of controller devices, the method further comprising: determining, by the second processor, the plurality of endpoints of the storage system; allocating, by the second processor, additional memory addresses to each of the plurality of endpoints; generating, by the second processor, an additional mapping table comprising one or more of the additional memory addresses allocated to one or more of the plurality of endpoints; and sending, by the second processor, the additional mapping table to at least the first controller device via the second switch.
 14. The method of claim 12, wherein sending the first message to the at least one SSD comprises sending the first message based on the mapping table.
 15. The method of claim 11, further comprising: connecting, by a second controller device of the plurality of controller devices, the storage system to one or more additional remote servers; receiving, by the second controller device, a second request from a second server of the one or more additional remote servers; determining, by the second controller device, whether the second request is a data request or a control request; and sending, by the second controller device, a second message to the first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the second request is a data request.
 16. The method of claim 11, further comprising: determining, by the first processor, a first paired queue associated with the first SSD, the first paired queue comprising a first submission queue and a first completion queue, wherein the first paired queue is to reside in a memory of the first controller device; and determining, by the first processor, a second paired queue associated with a second SSD of the plurality of SSDs, the second paired queue comprising a second submission queue and a second completion queue, wherein the second paired queue is to reside in the memory of the first controller device.
 17. The method of claim 11, further comprising: receiving, by the first controller device, a second request from a second server of the one or more remote servers; determining, by the first controller device, whether the second request is a data request or a control request; and forwarding, by the first controller device, the second request to the first processor via the first switch responsive to a determination that the second request is a control request.
 18. The method of claim 11, wherein the first root complex is a master and the plurality of SSDs and the plurality of controller devices are peers.
 19. The method of claim 11, further comprising: exposing, by the first controller device, a first virtual drive to the first server, wherein the first request comprises a virtual address of the first virtual drive; and translating, by the first controller device, the virtual address into a physical address of at least one SSD of the plurality of SSDs using a translation table.
 20. A storage system comprising: a storage array comprising a plurality of solid state storage devices (SSDs); a plurality of controller devices, each of the plurality of controller devices to connect the storage system to one or more remote servers; a first processor comprising a first root complex of the storage system; a first switch to interconnect the plurality of SSDs, the first processor and the plurality of controller devices, wherein the plurality of SSDs and the plurality of controller devices are peers of the storage system; a second processor comprising a second root complex that acts as a second master of the storage system; a second switch to interconnect the plurality of SSDs, the second processor and the plurality of controller devices; wherein the first processor is to: determine a plurality of endpoints of the storage system, the plurality of endpoints comprising the plurality of controller devices and the plurality of storage devices; allocate memory addresses to each of the plurality of endpoints; generate a mapping table comprising one or more of the memory addresses allocated to one or more of the plurality of endpoints; and send the mapping table to at least a first controller device of the plurality of controller devices via the first switch; and wherein the first controller device is to: receive a first request from a first server of the one or more remote servers; determine whether the first request is a data request or a control request; and send a first message to a first SSD of the plurality of SSDs via the first switch, bypassing the first processor, responsive to a determination that the first request is a data request. 